The Winchester '73 is the most popular rifle in cowboy action shooting so I know a little about them.
There are four sources for 1873s. You can buy an original Winchester made between 1873 and the 1920s. Of course, none of those were chambered in .45 Colt which was strictly a revolver cartridge until very recently. I saw one for sale in my local Cabela's store the other day (a .32 WCF); they are usually very expensive.
There was a reproduction imported a few years back by a company called Chaparral. CDNN Sports had them for a while. These don't have a good reputation and they are no longer imported and possibly no longer made. I'd avoid them.
Uberti has been making reproductions of the '73 for many years. They make them in several variations of finish, barrel length, stock type, etc. They are imported by several US distributors including Stoeger (which like Uberti is part of the Beretts family of companies), Taylors & Company, Cimarron Firearms and probably others I have forgotten. They are pretty good guns but they really benefit from a little tweaking. New prices start a little north of $1,000 depending on which variant you choose. There is a good bit of aftermarket support for these guns because they are so heavily used by cowboy action shooters.
The one you linked is a "modern" Winchester '73 that is made by Miroku in Japan, the company that makes many of the Browning guns. I think they've been making the '73 for about four years now. Miroku is a quality manufacturer and many shooters think this rifle is a little better out of the box than the Uberti. It is also a little more expensive, there is not much aftermarket support and there are fewer variants as compared with Uberti.
Some .45 Colt rifles of various brands suffer from a condition we call "blowby" in which gas flows back from the chamber into the shooter's face. It is particularly evident with light loaded rounds. Not all rifles do this but some that do can be rather unpleasant to shoot. My Uberti '73 is a .357 but if I were shopping for a big bore I would choose the .44-40 (aka .44 WCF), which was the original chambering of the Winchester 1873 when it was introduced in (you guessed it) 1873. It has a slightly bottlenecked case with comparatively thinner case walls (compared to the .45 Colt) and tends to seal the chamber very well. People who shoot black powder cartridges love the .44-40 and its "cousins", the .38-40 and the .32-20.
The '73 is a great rifle but you gotta pay to play. About the cheapest I have seen a good used '73 reproduction sell for is about $700.
